\begin{tikzpicture}
    \tkzDefPoints{0/0/B, 2.5/0.5/C}
    \tkzDefTriangle[equilateral](B,C)  \tkzGetPoint{A}
    \tkzDefCircle[circum](A,B,C)  \tkzGetPoints{O}{R}
    \tkzDefTriangle[two angles=80 and 40](B,C)  \tkzGetPoint{P}

    \tkzDrawCircle[thick](O,R)
    \tkzDrawPolygon(A,P,B,C)
    \tkzDrawSegments(A,B  C,P)
    \tkzDrawPoint(O)
    \tkzLabelPoints[below](O)
    \tkzLabelPoints[above](A)
    \tkzLabelPoints[left](B)
    \tkzLabelPoints[right](C)
    \tkzLabelPoints[above](P)
\end{tikzpicture}

